module ecs.entity;

import ecs.manager;

struct EntityID
{
    uint id;
    uint counter;
}

struct Entity
{
    EntityID id;

    void updateID()
    {
        EntityManager.instance.id_manager.update(this);
    }

    T* getComponent(T)()
    {
        EntityManager.EntitiesBlock* block = gEM.getMetaData(&this);
        EntityManager.EntityInfo* info = block.type_info;
        if (T.component_id >= info.deltas.length || info.deltas[T.component_id] == 0)
            return null;
       
        static if (EntityID.sizeof == 8)
            uint ind = cast(uint)((cast(void*)&this - block.dataBegin()) >> 3);
        else
            uint ind = cast(uint)((cast(void*)&this - block.dataBegin()) / EntityID.sizeof());
        return cast(T*)(cast(void*)block + info.deltas[T.component_id] + ind * T.sizeof);
    }
}

export struct EntityTemplate
{
    ubyte[] entity_data;
    EntityManager.EntityInfo* info;

    T* getComponent(T)()
    {
        if(T.component_id >= info.tmpl_deltas.length)return null;
        return cast(T*)(entity_data.ptr + info.tmpl_deltas[T.component_id]);
    }
}